This invention is in the field of data acquisition systems. More particularly, it is in the field of data gathering systems which involve a high plurality of separate detectors and channels, the signals from which are carried to the data storage means by a single pair of conductors.
While this invention is useful in the acquisition of any type of analog signals such as in the field of data collection, vibration analysis, sonar signaling, nuclear technology, and so on, it is most appropriately useful in the area of seismic prospecting and as a matter of convenience will be discussed in that application. This description in terms of a seismic system does not limit in any way the scope of this application and its use in other fields of data acquisition.
In the prior art, seismic operations have been carried out with field instrumentation systems which have, in general, been limited by size, weight and power requirements to 24-48 separate recording channels. Additional recording channels have been provided by the process of adding additional recording truck units, and so on. Although there have been suggestions in the technical press for multiplex recording systems whereby high pluralities of recording channels can be provided using a single conductor pair for the transmission of the separate traces there have been no practical ways shown for carrying out such suggestions. Furthermore, those that have been suggested call for control and processing devices in series with each signal channel at considerable complexity and cost.